CODEWITHSUNDEEP
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aMighty
aMighty

Reputation: 283

Regex is not working in RegularExpression Annotation

I have applied client side validation using RegularExpression Annotation in ViewModel.

The validation is GroupName should startwith either TPDC_ or DMK_ with atleast one more letter

[Required(ErrorMessage = "Group Name is required")]
        [RegularExpression("^(TPDC_|DMK_)+", ErrorMessage = "Group Name should begin with TPDC_ or DMK_")]
        public string GroupName { get; set; }

But the regex used is not working as expected.

Upvotes: 1

Views: 47

Answers (2)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626748

If you plan to match a string that starts with TPDC or DMK and then has a _ followed with one or more letters, you may consider using

^(TPDC|DMK)_[A-Za-z]+$

Or, if after _, there may be any characters, but a letter is required to appear somewhere, you may use

^(TPDC|DMK)_[^A-Za-z]*[A-Za-z].*

See regex demo #1 and regex demo #2.

Details

  • ^ - start of string
  • (TPDC|DMK) - either TPDC or DMK
  • _ - an underscore
  • [A-Za-z]+ - 1+ ASCII letters (\p{L}+ will only work on the server side!)
  • [^A-Za-z]*[A-Za-z].* - any 0 or more chars other than ASCII letters (\P{L}* is the Unicode equivalent of [^A-Za-z]* that will only work on the server side), an ASCII letter, and then any 0 or more chars other than line break chars, as many as possible.
  • $ - end of string.

Upvotes: 1

The fourth bird
The fourth bird

Reputation: 163277

You don't need to repeat the group with the alternation. If you want the following letter to be A-Z you could add a character class after it. The underscore might be moved to after closing the group.

^(?:TPDC|DMK)_[A-Z]

Explanation

  • ^ Start of string
  • (?: Non caputure group
    • TPDC|DMK Match TPDC or DMK
  • ) Close group
  • _[A-Z] Match an underscore followed by a char A-Z

Regex demo

Or if you want to allow any letter from any language you could use \p{L} instead

^(?:TPDC|DMK)_\p{L}

Upvotes: 1

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